1.) Field of the Invention
The present invention is a new, reusable growing container that reduces unfavorably high temperatures within a plant's root ball and produces a beneficially modified root system by a technique called "air-root pruning." Both of these factors in turn produce a superior quality plant and alleviate trauma during transplanting of nursery grown trees and plants.
2.) Description of the Prior Art
Since the mid-twentieth century, commercially grown plants have been cultivated in some type of container that provides ease of management and transportation. The container grown plant was immediately recognized as being beneficial over the traditional field grown plant, because the root systems were neither cut nor damaged when transported to a landscaping site. Over the years, nursery owners have developed ways of improving plant production with examples like new types of fertile media to environmentally safe pesticides and herbicides. Possibly, the most important fact recently discovered was that reducing the girdling of roots, created by solid plastic containers, increases not only a plant's growth and health but also its aesthetic quality.
In the past few decades, the popularity of the plastic container has grown rapidly and is now used consistently among nursery owners. Though popular, several drawbacks have been noted and supported by many research institutions.
First, these plastic containers conduct heat that can intensify root ball temperatures to unfavorable conditions, especially in nurseries located in warmer climates. This fact causes increased evapotranspiration and in turn creates a favorable environment for plant wilt. To combat this problem, nurseries have to increase watering times and water usage which is undesirable in this decade of needed water conservation.
Secondly, root systems are allowed to become circular within the plastic container producing a girdling effect, consequently reducing the effectiveness of growth before and after transplanting. Stunted growth and slow adaptation at a newly planted landscape site are recognizable results of an unmanaged root system.
Among these noted disadvantages exist positive concepts about the plastic container that should not be overlooked when developing new types of growing containers. One economical benefit offered by the plastic container is its ability for re-use in the nursery. A nursery owner can also appreciate its shape which allows for convenient storage and space conservation.
Lately, several different types of manipulated plastic containers have surfaced commercially demonstrating the air-root pruning technique that aids in the prevention of spiraling and circular root patterns. Air-root pruning is a method by which root tips are burnt when exposed to air. This causes the root to discontinue growth and branch outward into several new root tips. The branching effect is very beneficial because it is these laterally spreading root tips that provide the plant with the most uptake of water and nutrients necessary for survival. In solid containers, roots have no release possibilities essentially causing a plant's root system, after a substantial growth period, to "choke" and hinder its longevity of life.
Patented containers such as U.S. Pat. No. 4,442,628, issued Apr. 17, 1984, used notched sections within the container's sidewall to trap root tips causing them to die off and produce root branching. This procedure was not fully successful and led to a predecessor that was U.S. Pat. No. 4,497,132, issued Feb. 5, 1985. This second root pruning container also did not produce great results because spiraling roots still occurred, but lateral root branching was numerous. So, a third root pruning container in this line, U.S. Pat. No. 4,753,037, issued Jun. 28, 1988, was designed with not only root trapping compartments but also intricate cuts in the sidewall of the container to allow for the air-root pruning method to work. This third container was fairly successful but resulted in high manufacturing costs and thus became uneconomical for nursery owners.
The U.S. Pat. No. 5,241,784 issued Sep. 7, 1993, refers to an aluminum grow ring that was recently introduced into the horticulture market. This new air-root pruning grow ring has been successful in stopping the girdling effect caused by solid plastic containers, but the use of aluminum material as a sidewall has two major drawbacks.
First, the aluminum aids in the increasing of root temperatures which is not desired by growers. A favorable nursery conditions for maximum foliage growth of many plants is to allow for ample spacing between the plants. When spaced out properly, a container is then subject to the sun's rays and the chance of increased root ball temperatures. The direct sunlight's heat is not reflected, but absorbed by the aluminum container increasing root ball temperature to unfavorable conditions for maximum growth.
Secondly, the high production cost of the completed aluminum ring is not only a burden financially, but it also pressures the nursery owner into removing the ring before shipping for reuse. This leaves container grown plants to be transported without any support around the root ball. When root balls are not supported by a container the consequences could be fatal if plants are mishandled or not planted within a reasonable amount of time once on the landscape site.
The present invention provides a solution for all the previously mentioned reoccurring problems. The use of polypropylene fabric allows root balls to not only "breathe" in order to fight high temperatures, but also has proven very successful in utilizing the air-root pruning technique. The absolute stopping of root girdling and the increase in lateral root growth allows the said trees and plants to adapt very well at landscape sites.
With it being very economical to produce, at under half the cost of the aluminum grow ring, the present invention allows nurseries to transport plants with the container supporting the root ball. This factor also adds to the success rate of said trees or plants at landscape sites. Therefore, the present invention represents a new generation design of temperature controlling, air-root pruning containers.